The impact of the extension of the post-natal in the adherence to breastfeeding Cohort study.

Introduction: In Chile, Law 20,545 came into force in 2011, extending the maternity leave from 12 to 21 weeks. The National Breastfeeding Survey (ENALMA, in Spanish), applied after the extended maternity leave, reported a 12% increase in adherence to exclusive breastfeeding (EBF) at the sixth month. However, 63% of the women surveyed were unemployed, therefore, the main causes of cessation of breastfeeding (BF) were not related to maternal rest time. Objectives: To calculate the impact of changes in the EBF adherence in patients who attend to well-child visits in the period before and after the entry into force of the extended maternity leave. Materials and Methods: Data were collected from electronic medical records of the San Joaquin Health Center between 2009 and 2013, which were recruited according to specified inclusion and exclusion criteria (n = 938 patients). Subsequently, they were divided into two groups according to the presence or absence of the extended maternity leave and with follow-up at three, six and 12 months. Using frequency tables, the characterization of the groups was carried out at the beginning of the observation period. To evaluate group homogeneity, study variables were compared between groups using Chi-square and Wicolxon Mann-Whitney tests. The prevalence of EBF maintenance was compared by pr-test between the groups with follow-up at three, six and 12 months. Using survival analysis and Cox regression, the impact of the extended maternity leave effect between both groups in the first 12 months was calculated. Results: At the beginning of the observation periods, no differences were observed between the groups in the studied variables. When comparing groups, without and with extended maternity leave, there were no significant differences in EBF adherence at three months: 327 (66%) versus 302 (68%), p = 0.492, respectively. However, in the groups in follow-up at six and 12 months, there was an increase in EBF adherence from 164 (33%) to 187 (42%), p = 0.004 and from 51 (10%) to 72 (16), p = 0.007, respectively. Analyzing the impact of the maternity leave extension on the adherence to breastfeeding, determined by risk ratio, this extension may positively influence on the adherence to EBF over time, with a HR < 1 (HR 0.852, p=0.04 CI 95%: 0.728-0.996). Conclusion: Increased maternal resting time may influence as a protective factor for adherence to EBF.